Abstract: SA-PO196

Role of Exocyst Complex in Podocytes

Session Information

  • Glomerular: Cell Biology
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Glomerular

  • 1003 Glomerular: Cell Biology

Authors

  • Solanki, Ashish K., Medical University of South Carolina, Charleston, South Carolina, United States
  • Ghoshroy, Soumitra, University of South Carolina, Columbia, South Carolina, United States
  • Nihalani, Deepak, Medical University of South Carolina, Charleston, South Carolina, United States
  • Arif, Ehtesham, Medical University of South Carolina, Charleston, South Carolina, United States
  • Srivastava, Pankaj, MEDICAL UNIVERSITY OF SOUTH CAROLINA, CHARLESTON, South Carolina, United States
  • Lipschutz, Joshua H., Medical University of South Carolina, Charleston, South Carolina, United States
  • Zuo, Xiaofeng, MEDICAL UNIVERSITY OF SOUTH CAROLINA, CHARLESTON, South Carolina, United States
  • Su, Yanhui, MUSC, Charleston, South Carolina, United States
  • Dang, Yujing, Medical University of South Carolina, Charleston, South Carolina, United States
  • Alsudani, Habeeb, USC, Columbia, South Carolina, United States
Background

Exocytosis is mediated through the exocyst complex, which is critical for protein transport and its disruption causes defects in various cellular processes including cell polarity, migration, ciliogenesis and autophagy. Since various glomerular injuries disrupt these processes, we hypothesized that disruption of exocytosis in podocytes will lead to a disease phenotype. In this study, we generated podocyte-specific Exoc5 (a central component of the octameric exocyst complex) knockout mice that showed massive proteinuria and died within 4 weeks of birth.

Methods

Exoc5 was genetically deleted in podocytes by crossing Exoc5f/f with pod-CreTg/+ mice. Mice were analyzed using biochemical, histological, morphological and immunofluorescence approaches. Exoc5 knocked down stable cultured podocyte cells were created using Exoc5-specific shRNA and stained with acetylated tubulin and ciliary phenotype was evaluated by superresolution microscopy.

Results

The Exoc5f/f;PodCreTg/+ mice were proteinuric and died between 21-27 days after birth. Kidney section analysis showed severe glomerular defects with increased fibrosis and proteinaceous casts. Ultrastructural analysis showed effaced podocytes with loss of slit diaphragm. Immunofluorescence analysis showed significant mislocalization of junctional proteins Neph1 and ZO-1, and decreased Nephrin protein expression. To study ciliogenesis defects, we stained isolated mice glomeruli with tubulin antibody, which showed numerous cilia on wild type (WT) glomeruli (Fig1), while cilia in Exoc5 KO glomeruli were absent. In contrast, cultured podocytes showed reduced cilia number with shortened length.

Conclusion

This is the first report that highlights role of exocyst complex in podocytes and shows that loss of Exoc5 results in massive glomerular damage, loss of cilia and death in mice.

Funding

  • NIDDK Support